Sparks Electrical News February 2020

ENERGY EFFICIENCY

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The future calls for efficiency T he demand for raw materials is rising, which means reserves should be dwindling. Produc- ers around the world are thus working towards the goal of generating more with less. The result, which seems contradictory at first glance, is that reserves are increasing thanks to technological innovations.

the necessary investments are increasing and yields are sinking, such as with gold, which can be found in nearly all electronic products in tiny amounts. The technical trends are already becoming visible. In mining, for instance, complex chemical processes or bioleaching with bacteria aims to make it easier to release the minerals from the rock. The underground mining sector is also seriously considering highly automated extraction methods. Real-time mining, an EU-sponsored research and innovation project, has named two major objectives: decrease environmental impact; and increase resource efficiency. Achieving these goals will require continuous process monitoring and highly selective mining operations, thus resulting in less energy consumption and less excavated material. If the industry is successful in making this transformation, reserves will continue to grow. This is a trend that has long been observed as a consequence of new exploration and technological advances, such as with copper. In 1970, usable copper reserves were estimated at roughly 280 million tonnes. That number has since risen to between 600 and 800 million tonnes, despite the fact that the industry mined around 520 million tonnes over the past five decades. Recycling raw materials Reserves also increase when the recycling loops are effectively closed. In contrast to other raw materials, metals can be recycled over and over because they are used, not consumed. A third of copper production is al- ready covered through recycling today. At around 800 million tonnes a year, steel is the world’s most recycled material. However, the much-discussed concept of ur- ban mining – the process of recovering raw materials from used products, buildings and waste – has so far turned out to be more of a concept than a reality. Electronic scrap stored at old and new waste disposals is viewed as a major source of secondary raw materials for the future. However, it is still unclear how these resources can be systematically developed, not to mention the fact that themixture of substances requires exceptionally complex separation processes. Recycling is a topic of discussion in cement manufacturing as well, where enormous quantities are needed to produce concrete for growing cities around the world. The fields of application for recycled materials are limited, but there is much that can be accomplished in other areas. At 65 to 75 percent of the variable manufacturing costs, energy is a critical factor in the burning of the cement clinker. Alternative raw materials, secondary fuels such as sewage treatment sludge, and more efficient kilns, can help to drastically reduce the consumption of rock and fossil fuels, and thus carbon emissions. Steel is no different. Up to 40 percent of the production costs are tied to energy utilisation. Both industries are under pressure to develop new solutions to satisfy more stringent environmental regulations around the world. This applies to the mining industry as well, with emerging future technologies changing the needs of the market. Because of the electro- mobility boom, for instance, the demand for lithium, cobalt and nickel is growing. Data is the key Although the primaries industry operates in a marked- ly physical world, the various segments have one thing in common: to implement the necessary innovations, precise and continuous data is required – and it has to be linked so that all of the individual processes can be flexibly controlled in minute detail. “There are a num- ber of things that we could use this data for, such as faster mine planning, more efficient system operation, automation of the extraction process and improving the processing technologies,” concludes Michelle Ash, chair of the Global Mining Guidelines Group, which is driving the transformation of the global mining in- dustry. “Generally speaking, developments suggest that the real catalyst for fundamental change in the way materials are produced could be cyber-physical systems. Maybe resource scarcity won’t result in bad times for the industry after all. Perhaps it’s just the op- posite, a brighter future through better technology.”

distributed unequally. Most of the large deposits have already been developed, while cannot be economically used since they are too finely dispersed to be easily extracted or lie in inaccessible regions. The resource crisis in perspective Under pressure from all sides, the phrase ‘resource crisis’ is used on a regular basis, sometimes with a fo- cus on scarce or uncertain supplies, other times with concerns about the price structure. Geopolitical issues play a role as well, given that access to the deposits is often confined to narrow geographical areas, and

on the markets national trade policies consequently meet global industry structures. On the other hand, the way in which metals and minerals are wrested from the earth often concerns environmentalists. The objective is to make the extraction of raw materials more sustainable by reducing both energy consump- tion and the impact on nature. As a result, raw ma- terials producers are feeling pressure from all sides. Although demand for their products is high, geopo- litical frameworks, price sensibility and political de- mands are making the business anything but simple. Approval processes are becoming more complicated,

Whileourplanetboastsawealthofnaturalresources, industrialised nations and the large emerging ones, especially China and India, are developing an ever- increasing appetite for raw materials. Furthermore, the reserves – those resources that can be extracted economically and with today’s technology – are often

Finding an effective power solution for blackouts and load-shedding I n South Africa, the flicker of a light bulb or the sound of a buzzing electrical appliance has become a cause for celebration. The realisa- tion of power returning brings on a sigh of relief. Africa’s second largest economy has threatened to regress as rolling blackouts keep the country in the dark. The blackouts are scheduled and limited, affecting different areas at different times, in a process meant to convey stability, even as the national grid struggles. These organised power cuts are known as ‘load shedding’ (blackouts).

Load-shedding, or load reduction, is undertaken countrywide as a controlled option to respond to unplanned events to protect the electricity power system from a total blackout. A country-wide blackout has serious consequences, which can occur when there is too much demand and too little supply, bringing the power system into an imbalance – shutting the power system in its entirety. With the increase in load-shedding, we are reminded about the inconvenience of no power. Whether planned or an accidental ‘blackout’, the power returns with a power-back surge causing damage or even destroying electrical appliances. During planned load shedding, cable thieves may steal copper cables resulting in loss of neutral. This results in equipment receiving 3-phase (+400 V) and not the 220-230 V, again damaging electrical appliances. 5 main power problems: The following problems can negatively impact the solar inverter if the right pro- tection isn’t correctly installed to prevent the below events from occurring whilst in function;

1. High voltage – As power fluctuates due to unreli- able mains or poor distribution network, the mains voltage can either drop or rise. A sustained over volt- age event can be catastrophic and cause instant ir- reparable damage. (Consider installing a SVS, voltage stabiliser, where utility is supplying high/over voltage for long durations. This will facilitate faster charging of the batter pack). 2. Low voltage – Similarly, low voltage can occur often during fluctuations, over stretched distribution network, excessive demand to the size of the utility or being at the end of a long distribution line. Low voltage is par- ticularly damaging to equipment. (Consider installing a SVS, voltage stabiliser, where utility is supplying low/ brown out voltage for long durations. This will facilitate faster charging of the battery pack). 3. Power back surges – Commonly occur after power cuts. As the mains supply resumes, it usually returns with a surge which could be quite high and damaging in some instances. Ensuring the power has settled be- fore resumption is important. 4. Spikes and surges – Power spikes are short pulses of energy on a power line and contain high voltage. These spikes only last a few milliseconds, but they have the potential to cause great damage to sensitive equipment. Often equipment does not fail right away; however, in many instances when it does, this seriously affects the shelf life of any electrical equipment. 5. Loss of neutral – When the instance of LoN occurs, the line voltage will rise from a normal 220/230 to 400/415 V causing instant catastrophic damage and even risk of fire. The AVS30 inverter accepts the input power source from the ac mains, battery, solar modules and switches between various operation modes depending on the operational conditions. This will expose the inverter to high or low voltage, which will damage its circuitry. The AVS is installed to protect the inverter from unreliable damaging mains power by disconnecting the input main power when it’s outside the limit of acceptable voltages.

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SPARKS ELECTRICAL NEWS

FEBRUARY 2020